Hi! I am currently trying to implement a new graph type which I want to use with the BGL. The graph implements the Incidence Graph concept and should work out of the box with DFS algorithm of the BGL. However, I had to find out that the edge_descriptor must obey an EqualityComparison concept which keeps DFS from compiling. My current edge_descriptor is just a typedef to std::pair<vertex_descriptor, vertex_descriptor>. The vertex_descriptor itself is a custom object I wrote myself. Another problem turns out to appear with the copy-graph algorithm. This algorithm tries to copy vertex_all-property maps and edge_all property maps which I simply do not have defined in my custom graph as I only support the vertex_index mechanism. So what to do here? How can I tell copy-graph that these maps are not existent? Any help would be great here as I have the impression to hit limits of the documentation (the Equality-thing is not mentioned in the docs, at least I did not find it...). Greetings, Sebastian